1. Field of the Invention
The present invention relates to a wheeled travois for towing supplies and other loads behind an individual. The wheeled travois of the present invention is particularly useful for towing supplies and other loads over uneven terrain.
2. The Prior Art
The prior art presents a diverse array of embodiments of different devices which may be employed to tow or carry a load behind an individual. The object of these devices is to assist an individual in transporting a load, especially those loads weighing more than an individual may comfortably carry for any significant distance. Though many different types of carriers exist, including carriers which are handheld and may be either pushed or pulled and carriers which are attached to and towed behind an individual, each of the carriers found in the prior art have at least one of several problems including stability, limitations of maneuverability or desirability of function. Of particular interest herein are carriers with a load carrying frame having a single wheel structure which may be attached to and towed behind an individual.
Prior art descriptions of carts or carriers employing a single wheel structure that may be either pushed or pulled include Murphy, U.S. Pat. No. 3,055,449; Strand, U.S. Pat. No. 3,550,997; Tracy, et al., U.S. Pat. No. 3,560,015; Fraser, U.S. Pat. No. 4,063,744; and Cockram, U.S. Pat. No. 4,171,139. Of these, Tracy, et al. and Strand disclose a backpack frame which upon removal may be converted to a single wheeled cart.
There are several readily apparent advantages to be gained with a travois structure which incorporates the features of a single wheel and an attachment for towing behind an individual. These features when embodied in a travois will narrow its profile, free the hands of the user, and allow the user to travel a greater distance with the load. However, attempts in the prior art to embody these features have not been satisfactory.
A common design disclosed by the prior art teaches a travois which is attached to the user at two points, and includes embodiments where the attachment is made to either a belt or an over the shoulder harness worn by the user. While the use of two points of attachment creates a stable arrangement, it imposes as substantial trade-offs unwanted limitations on maneuverability and desirability of use due in part to limitations on side to side movement and additional weight in the frame. Embodiments of a travois using two points of attachment may be found in Giovannoni U.S. Pat. No. 2,613,953, Lagant U.S. Pat. No. 2,655,957, Fails U.S.Pat. No. 4,045,040, and McCoy U.S. Pat. No. 4,664,395. Of these the Fails embodiment also undesirably uses a two wheel structure.
An embodiment of a travois employing a single wheel assembly and incorporating a single point of attachment is disclosed in Douglas U.S. Pat. No. 5,005,844. However, the mechanism used at the point of attachment creates an inherent instability. If the longitudinal axis of the travois lines up, even approximately, with the vertical axis of the attachment mechanism the travois and load will roll on its side. This will happen on most steep slopes. If the attachment mechanism is turned 90 degrees so the horizontal portion is on the user worn backpack the travois will roll whenever the user makes a hard turn. These inherent instabilities necessitate the use of an large roller assembly as the single wheel element or handles for the user to keep the load carrying frame in an upright position as well as a larger frame. This undesirably adds weight and severely decreases maneuverability.
b 3. Objects and Advantages.
The objects and advantages of the invention described herein are many. They are, but are not limited to, those described below.
A first object of the present invention is to provide a monowheel travois which overcomes some of the shortcomings of the prior art.
Another object of the present invention is to provide a monowheel travois which employs an abbreviated backpack frame that distributes the load from the load carrying frame to the individual. This has the advantage of providing a less cumbersome more maneuverable assembly with less weight and fewer pieces.
A further object of the present invention is to provide a monowheel travois which employs an attachment between the backpack and the load carrying frame that will allow the travois to move side to side (yaw) and up and down (pitch) relative to the user without allowing the travois to roll from an upright position. This enables the travois to be supported at it's lower end on a wheel made up of a single disk allowing a narrower profile than the prior art arrangements. The advantages to this configuration are numerous, including the ability to follow the user down narrow trails, and to squeeze between trees and other obstacles.
Yet another object of the present invention is to provide a travois which may be quickly released from the user's backpack. This has obvious advantages in an emergency and is useful at any time the user wants to separate from the travois
A further object of the present invention is to provide a monowheel travois which employs a load carrying frame configured so that it may be dragged over obstacles too big for the wheel to roll over. The advantage to this is that there is virtually no terrain that the travois cannot traverse.
Another object of the present invention is to provide a monowheel travois which can be carried in a similar manner to a standard backpack without the wheel on the ground. The advantage here is that it can be carried over terrain that it cannot roll over.
Another object of the present invention is to provide a monowheel travois which employs a single braking system that can apply variable braking pressure to the wheel and continuously lock the wheel for steep descents. The locking feature is also valuable when the travois is not in use and resting on the ground.
Yet another object of the present invention is to provide a monowheel travois which employs a load carrying frame configured so that the center of gravity of the load is below the center of gravity of the travois. The load must also be placed so that it does not interfere with the users normal stride. This creates a very stable arrangement that is not prone to roll over and is very maneuverable.
A final object of the present invention is to provide a monowheel travois which employs a wide range of adjustment in length and backpack attachment points. This enables the travois to fit a wide range of user body types comfortably, The Travois should also break down into pieces small enough to fit into a average automobile trunk.
Other advantages to the present invention will become evident in the following descriptions.